JPS59171318A - Programmable switch circuit - Google Patents

Abstract

PURPOSE:To improve the circuit integrating density and operating speed and to realize low power consumption by connecting a connecting point between a fuse element and a high resistive element to a gate of an MOS transistor (TR) having a transfer gate function directly and connecting a capacitor in parallel with the high resistive element of the fuse circuit. CONSTITUTION:The fuse circuit comprising a series circuit of the fuse element F and the high resistive element RL is provided between a ground potential source VSS and a power supply terminal VCC. The capacitor C1 is connected in parallel with the high resistive element RL of the fuse circuit. When the fuse element F is not blown and a signal applied to a terminal 1 of the MOSTR T is a signal changed pulsively, the changing state of this signal is fed back to a connecting point A to the fuse circuit via a gate capacitor CG and since the potential at the said connecting point A is set via the fuse element of a low resistance in this case the operation of the MOS TRT is made stable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention d: relates to a nonogrammable switch circuit used as a redundant circuit in semiconductor devices such as T, SI, etc.

[Technical background of the invention]

In recent years, the degree of integration of MOS LSIs has increased significantly, but with this increase in degree of integration, the rate of occurrence of defects in elements in one semiconductor pellet has increased, and circuits have also become larger and more complex. Let's yield υ for this useless semiconductor
In order to improve this, redundant circuit technology as a defect relief technology and redundant circuit technology aimed at improving the degree of freedom in design or increasing the operating margin are attracting attention.

As one of the redundant circuit technologies described above, a programmable fuse element and a transfer circuit that turns on and off according to the program state of the fuse element are installed in the main circuit having a predetermined function. Some devices add a redundant circuit of a so-called programmable switch circuit configuration consisting of a circuit and set the state of the main circuit by this redundant circuit.

An example of a conventional programmable switch circuit having a transfer function of this type is shown in FIG. In the figure, a heating element F whose one end is connected to the power source terminal Vec
and a high resistance element R whose one end is connected to a ground potential source vs[l
A so-called fuse circuit consisting of a series circuit with L is constructed. The connection point A between the high resistance element IRL and the fuse element F is an N-channel MO8) transistor Nl and a P-channel M.
O8) It is connected to the input point of an inverter circuit having a CMO8 configuration, which is connected in series with transistor P, and the output terminal B of the inverter circuit is connected to the date of the MOS transistor T that constitutes the transfer circuit. It is connected to a part of this transfer dart R-H1 dual circuit 7, and the state of the main circuit is appropriately set depending on the conduction cutoff state of this transfer dart.

In such a redundant circuit, when the fuse element F is in the connected state, the dirt potential of the MOS L transistor state becomes v
becomes 0 level and MOS transistor T becomes N channel M.
If it is O8, the transfer dart is turned off. In addition, when the fuse circuit F is in a disconnected state, the r-to potential of the N-channel MO8 transistor T is
The transfer rate becomes cc level and the transfer port is turned on.

Conversely, when the MOS transistor T is configured with a P-channel MO8, when the fuse element F is in the connected state, the transformer gate formed by the MOS transistor T is turned on, and the fuse is turned on. When the element F is in the disconnected state, the transfer shaft is in the off state.

A signal related to setting the state of the main circuit (not shown) is supplied to either the source or the drain of the transistor T, which serves as the transfer dart, or to the terminal 1. If the transfer dart is in the on state, this signal is propagated to the terminal 2, and the transfer When dart is in the off state, the signal at terminal 1 is not propagated to terminal 2.

[Problems with background technology]

By the way, in the above-mentioned circuit, the inverter provided between the fuse circuit and the transfer circuit occupies a large area, which completely hinders the improvement in the degree of integration of the semiconductor device.

However, this inverter was necessary to stabilize the operation of the programmable switch circuit. That is, in the MOS transistor T, there is an electrostatic capacitance (r-) capacitance CG between r-t, source, drain, and channel, and a change in the signal supplied to terminal 1 of the MOS transistor T is caused by this capacitance. It is fed back to f-) of the MOS transistor T via the date capacitor Co. Here, if there is no inverter and the first element F is in the disconnected state, the r-to potential is set via the high resistance element RL, so the change in the signal at the terminal 1 causes r- of MOS transistor T
The transfer f-to potential becomes unstable, and the operation of the transfer f-to becomes unstable.

In addition, the fuse circuit as described above and the transformer
In a programmable switch circuit having an inverter between the fuse circuit and the fuse circuit, a pulse signal such as a clock signal is sometimes supplied to one end of the fuse circuit instead of a constant potential source. In this case, the signal at the connection point A is passed through the inverter to the transistor T.
Since the inverter is supplied to the inverter, there is a delay in signal propagation, and the operation speed of the programmable switch circuit is low.Additionally, in this case, there is also the problem that the inverter consumes a large amount of power. .

[Purpose of the invention]

The present invention has been devised in view of the above points, and its purpose is to improve the integration density and operating speed, and to reduce power consumption, while improving the stability of circuit operation. The object of the present invention is to provide a simple 7'' O-gram switch and slave circuit with a simple configuration that can realize the following.

[Summary of the invention]

That is, in the programmable switch circuit according to the present invention, in a heating circuit consisting of a series circuit with a high resistance element and a high resistance element, the connection point between the heating element and the high resistance element is directly connected to the transfer function. MOS
) to the r-to of the transistor, and the above-mentioned beat.
A capacitor is connected in parallel to the high resistance element Rt of the circuit.

And, in practical terms, the gear/mother position is the upper
8) It is desirable to have a capacitance equal to or larger than the total capacitance tco of the transistor from rh to drain, channel, and source.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. As shown in FIG. 2, the ground potential source VIls and the power supply terminal ■.

, a fuse circuit consisting of a fuse circuit F and a high resistance element RLO1U column circuit is provided between. A gear resistor C1 is connected in parallel to both ends of the high resistance element RL of this fuse circuit.゛Still, connect directly to the top. This transistor T
No signal is supplied to the terminal Lj, which becomes the source or drain of Lj.

Here, the capacitance of the capacitor C1 is the capacitance value CaB+ CG extending from the r-t of the MOS transistor T to the source region, channel region, and tunnel region, respectively.
The sum of et CoD, that is, the total r-.t capacitance CG, is also set to be at least large. Further, in order to reduce power consumption when the high resistance element RL and the heating element F are in a connected state, their resistance values are selected to be 10 or more. In this embodiment, a high resistance element having a resistance value of 100 GΩ is used. (Usually, the range used is from the MΩ order to several tens of
It is about 0GΩ. ) Here, C1 fuse element F is in a connected state, and MOS )
If the signal supplied to terminal 1 of transistor T is a signal that changes in a thousand ruth pattern, the state of change in these months is r-
) is fed back to the connection point A of the fuse circuit via the capacitor MkCa, but in this case, the potential of the connection point A is set via the low resistance fuse element F, so the MO
S) The operation of Lanzostar T is stable.

Next, a case where fuse element F is in a disconnected state will be described. In this case, the potential at the series connection point A is set to a high potential V via the gear/coast C1 and the high resistance element RL.

It will be C level. Therefore, the MOS transistor T becomes conductive, and a signal propagates between terminals 1 and 2.

Now, if the signal propagating between terminals 1 and 2 is a signal that changes in a /4' loop shape, the changing state of this month is fed back to the connection point A of the fuse circuit through the r-t capacitor CG. However, this interference effect is reduced to rCa/(C10Ca)J due to the presence of the capacitor C1 connected in parallel with the high resistance element RL. For this reason, a transfer r consisting of a MOS) lansostar T
-T is a stable U1 player.

Of course, the MOS transistor T of the programmable switch circuit as described above is limited to an N-channel MOS P.
It can be configured with channel MO8, and in this case, the transfer gate's main off state is N channel MOS.
It will be the opposite of the lifting platform.

In the case shown in Fig. 3, the potential source supplied to the fuse circuit is connected to the entire circuit, and the connection/disconnection relationship of the fuse element F and the on/off relationship of the transfer terminal are shown in Fig. 2. This is the opposite of the embodiment.

The one shown in Figure 4 is a potential source connected to the resistor element side terminal of the fuse circuit in the programmable switch circuit of Figure 2.
Apply, for example, a clock signal φ instead of co, and apply a bias voltage v! to the fuse side terminal. It is designed to give l.

Here, when the fuse element F is in the connected state, the potential at the connection point A is identified by the bias voltage VB applied through the fuse element F, which has a very low resistance, and the transfer voltage r- The MOS transistor T is
Set to a constant state.

- On the other hand, when the fuse element F is in the disconnected state, the potential of the connection point A is set to the potential of the clock signal φ supplied to the parallel circuit of the high resistance element RL and the gear/disk capacitor C1,
MO of the transfer circuit according to the clock signal φ
S transistor T is controlled.

In this case, not only can the change in the signal transmitted via the MOS transistor T by the gear shifter C1 not reach the connection point A of the fuse circuit, reducing the influence, but also the clock signal φ can be transmitted with almost no delay. MOS transistor T
can be supplied to This is achieved by changing the clock signal φ to the MOS via the gear/mother C1 such that C1, ≧CG.
This is because there is no delay in the operation of the inverter that is supplied to the transistor T and is conventionally used.

Furthermore, not only the operating speed is improved, but since no inverter is required, power consumption can be reduced accordingly, and it is still possible to use CMO.
Compared to the S inverter, the gear (C) can be formed in a smaller area, so it is possible to increase the multiplication factor of the element.

In addition, in this case as well, as shown in FIG.

It is clear that the signal φ and the bias voltage 1lfr:O may be applied to the opposite terminals of the fuse circuit, and furthermore, the effects applied to the fuse circuit are not limited to the clock signal and the bias voltage VB. , it is possible to supply a pulse-like signal according to the control state of the main circuit as appropriate.

In addition, in the above embodiment, the capacitor C1O response amount is MOS
The capacitance of the transistor Tcl is larger than the capacitance CG (usually several fF to several hundred fF) (.IX), but the capacitance of the Φ capacitance C1 is the capacitance C shown above.

Even if it is smaller than that, some effect can be obtained.

However, setting q'; CG may be insufficient depending on the semiconductor device. By setting the capacity of Giano9SitaCt to about twice the amount of Ca in MOS) Lanzosta T), sufficient seedlings can be obtained in most specifications of semiconductor devices; Anything above that is even better. In this case, even if it is set to ξ3xc, for example, the area of the gear equalizer C1 is smaller than the element area occupied by a conventional CMOS-configured inverter.

[The moving bed of invention]

As described above, according to the present invention, it is possible to stabilize the operation of transfer f-1 without using an inverter that occupies a large area with four semiconductors, thereby improving integration density and operating speed. It is possible to provide a programmable switch circuit with a simple configuration that can realize low power consumption.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a conventional programmable switch circuit, and FIGS. 2 to 5 are circuit diagrams each showing an embodiment of the present invention. F...Fuse circuit, RL...High resistance element, C1.
・・Gianositor, T・・MOS transistor. 13- Figure 1 Figure 3 Figure 4?

Claims (4)

[Claims] (1) A series circuit of a bead element and a high-resistance element inserted between a first potential source and a second potential source, and a gear/nine gear connected in parallel to the high-resistance element, - 2. A programmable switch circuit characterized in that it comprises a transfer element consisting of a MOs transistor having an rh electrode connected to a series connection point between the heats element and the high resistance element. (2) The program according to claim 1, wherein the capacitor has a capacitance value larger than the total capacitance value between the date, drain, channel, and source of the transistor MO8). Possible switch circuit. (3) The programmable switch circuit according to claim 1 or 2, wherein the first and second potential sources are potential sources that provide a constant potential. (4) Claim 1 or 2, characterized in that at least one of the first and second potential sources is a potential source that provides a +-3 potential in the form of a square. Norogrammable switch circuit.